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Abstract:

An electrostatic loudspeaker includes: a first electrode having acoustic
transmission property; a second electrode having acoustic transmission
property, and disposed so as to be opposed to the first electrode; a
vibrating member having conductibility, and disposed between the first
electrode and the second electrode; a first elastic member having
elasticity, insulation property, and acoustic transmission property, and
disposed between the vibrating member and the first electrode; a second
elastic member having elasticity, insulation property, and acoustic
transmission property, and disposed between the vibrating member and the
second electrode; and a first separation member having insulation
property and acoustic transmission property, and disposed on an opposite
side of a face of the first electrode, which is opposed to the first
elastic member.

Claims:

1. An electrostatic loudspeaker comprising: a first electrode having
acoustic transmission property; a second electrode having acoustic
transmission property, and disposed so as to be opposed to the first
electrode; a vibrating member having conductibility, and disposed between
the first electrode and the second electrode; a first elastic member
having elasticity, insulation property, and acoustic transmission
property, and disposed between the vibrating member and the first
electrode; a second elastic member having elasticity, insulation
property, and acoustic transmission property, and disposed between the
vibrating member and the second electrode; and a first separation member
having insulation property and acoustic transmission property, and
disposed on an opposite side of a face of the first electrode, which is
opposed to the first elastic member.

2. The electrostatic loudspeaker according to claim 1, further
comprising: a second separation member having insulation property and
acoustic transmission property, and disposed on an opposite side of a
face of the second electrode, which is opposed to the second elastic
member.

3. The electrostatic loudspeaker according to claim 1, wherein the first
separation member has a hole opening from an inside of the first
separation member toward a face on an opposite side of a face of the
first separation member, which is opposed to the first electrode.

4. The electrostatic loudspeaker according to claim 3, wherein a holding
member is inserted into the hole.

5. The electrostatic loudspeaker according to claim 1, wherein the first
separation member has a hole in a circumferential face thereof.

6. The electrostatic loudspeaker according to claim 5, wherein a hook
member is inserted into the hole.

7. The electrostatic loudspeaker according to claim 1, wherein the first
separation member has elasticity.

8. The electrostatic loudspeaker according to claim 1, wherein the first
separation member is integrated with a main body having at least the
first electrode, the second electrode, the vibrating member, the first
elastic member, and the second elastic member using a restraining member
so as to be formed into one body.

9. The electrostatic loudspeaker according to claim 8, wherein the
restraining member has a belt shape.

10. The electrostatic loudspeaker according to claim 8, wherein the
restraining member is a member for covering the first separation member
and the main body.

11. The electrostatic loudspeaker according to claim 1, wherein the first
separation member has one face formed into a convex shape, and a main
body having at least the first electrode, the second electrode, the
vibrating member, the first elastic member, and the second elastic member
is provided on the one face.

12. The electrostatic loudspeaker according to claim 1, wherein the first
separation member has one face formed into a concave shape, and a main
body having at least the first electrode, the second electrode, the
vibrating member, the first elastic member, and the second elastic member
is provided on the one face.

13. The electrostatic loudspeaker according to claim 1, wherein the first
separation member has one face formed into a curved shape, and a main
body having at least the first electrode, the second electrode, the
vibrating member, the first elastic member, and the second elastic member
is provided on a face on an opposite side of the one face.

14. The electrostatic loudspeaker according to claim 1, wherein the first
separation member has a base and a plurality of protrusions provided on
one face of the base.

15. The electrostatic loudspeaker according to claim 1, wherein the first
separation member is a member in which a plurality of spaces having a
predetermined shape are joined together.

16. The electrostatic loudspeaker according to claim 15, wherein the
predetermined shape is a hexagonal shape.

17. A speaker system comprising: a loudspeaker's main body including: a
first electrode having acoustic transmission property; a second electrode
having acoustic transmission property, and disposed so as to be opposed
to the first electrode; a vibrating member having conductibility, and
disposed between the first electrode and the second electrode; a first
elastic member having elasticity, insulation property, and acoustic
transmission property, and disposed between the vibrating member and the
first electrode; and a second elastic member having elasticity,
insulation property, and acoustic transmission property, and disposed
between the vibrating member and the second electrode; and a separation
member having insulation property and acoustic transmission property, and
disposed on an opposite side of a face of the first electrode of the
loudspeaker's main body, which is opposed to the first elastic member.

18. A separation member mounted on a loudspeaker's main body having a
first electrode having acoustic transmission property, a second electrode
having acoustic transmission property, and disposed so as to be opposed
to the first electrode, a vibrating member having conductibility, and
disposed between the first electrode and the second electrode, a first
elastic member having elasticity, insulation property, and acoustic
transmission property, and disposed between the vibrating member and the
first electrode, and a second elastic member having elasticity,
insulation property, and acoustic transmission property, and disposed
between the vibrating member and the second electrode, wherein the
separation member has insulation property and acoustic transmission
property and is disposed on an opposite side of a face of the first
electrode of the loudspeaker's main body, which is opposed to the first
elastic member.

19. The electrostatic loudspeaker according to claim 2, wherein the first
separation member has a hole opening from an inside of the first
separation member toward a face on an opposite side of a face of the
first separation member, which is opposed to the first electrode.

Description:

TECHNICAL FIELD

[0001] The present invention relates to an electrostatic loudspeaker.

BACKGROUND ART

[0002] The push-pull electrostatic loudspeaker disclosed in Patent
Document 1 includes two flat electrodes opposed to each other with a
clearance therebetween and a membranous vibrating plate (vibrating
member) having conductibility and disposed between the flat electrodes;
when a predetermined bias voltage is applied to the vibrating plate and
the voltage to be applied across the flat electrodes is changed, the
electrostatic force exerted to the vibrating plate is changed, whereby
the vibrating plate is displaced. When the applied voltage is changed
depending on an acoustic signal to be input, the vibrating plate is
displaced repeatedly depending on the change, and an acoustic wave
depending on the acoustic signal is generated from both faces of the
vibrating plate. The generated acoustic wave passes through through-holes
formed in the flat electrodes and is radiated to the outside.

[0003] Furthermore, as an electrostatic loudspeaker having flexibility and
being foldable or bendable, the electrostatic loudspeaker disclosed in
Patent Document 2 is available. In the electrostatic loudspeaker, a
polyester film (vibrating member) on which aluminum is evaporated is held
between two pieces of cloth (electrodes) woven with conductive threads,
and ester wool is disposed between the film and the cloth.

PRIOR ART DOCUMENTS

Patent Documents

[0004] Patent Document 1: JP-A-2007-318554

[0005] Patent Document 2: JP-A-2008-54154

SUMMARY OF THE INVENTION

Problem that the Invention is to Solve

[0006] A push-pull electrostatic loudspeaker generates an acoustic wave
from both faces of the vibrating plate (vibrating member) thereof.
However, in the case that the push-pull electrostatic loudspeaker is
installed so as to be made contact with a shield through which the
acoustic wave hardly passes, such as a floor face or a wall face, the
acoustic wave generated toward the shield is blocked by the shield, and
there occurs a problem that the acoustic wave is not radiated to the
outside of the electrostatic loudspeaker.

[0007] Under the circumstances described above, an object of the present
invention is to provide a push-pull electrostatic loudspeaker capable of
radiating the acoustic wave generated from both faces of the vibrating
member thereof to the outside of the electrostatic loudspeaker even if
the electrostatic loudspeaker is installed so as to be made contact with
a shield through which the acoustic wave hardly passes.

Means for Solving the Problems

[0008] In order to solve the above problems, according to the invention,
there is provided an electrostatic loudspeaker comprising: a first
electrode having acoustic transmission property; a second electrode
having acoustic transmission property, and disposed so as to be opposed
to the first electrode; a vibrating member having conductibility, and
disposed between the first electrode and the second electrode; a first
elastic member having elasticity, insulation property, and acoustic
transmission property, and disposed between the vibrating member and the
first electrode; a second elastic member having elasticity, insulation
property, and acoustic transmission property, and disposed between the
vibrating member and the second electrode; and a first separation member
having insulation property and acoustic transmission property, and
disposed on an opposite side of a face of the first electrode, which is
opposed to the first elastic member.

[0009] In the invention, the electrostatic loudspeaker may further include
a second separation member having insulation property and acoustic
transmission property, and disposed on an opposite side of a face of the
second electrode, which is opposed to the second elastic member.

[0010] In the invention, the first separation member may have a hole
opening from an inside of the first separation member toward a face on an
opposite side of a face of the first separation member, which is opposed
to the first electrode.

[0011] In the invention, a holding member may be inserted into the hole.

[0012] In the invention, the first separation member may have a hole in a
circumferential face thereof.

[0013] In the invention, a hook member may be inserted into the hole.

[0014] In the invention, the first separation member may have elasticity.

[0015] In the invention, the first separation member may be integrated
with a main body having at least the first electrode, the second
electrode, the vibrating member, the first elastic member, and the second
elastic member using a restraining member so as to be formed into one
body.

[0016] In the invention, the restraining member may have a belt shape.

[0017] In the invention, the restraining member may be a member for
covering the first separation member and the main body.

[0018] In the invention, the first separation member may have one face
formed into a convex shape, and a main body having at least the first
electrode, the second electrode, the vibrating member, the first elastic
member, and the second elastic member may be provided on the one face.

[0019] In the invention, the first separation member may have one face
formed into a concave shape, and a main body having at least the first
electrode, the second electrode, the vibrating member, the first elastic
member, and the second elastic member may be provided on the one face.

[0020] In the invention, the first separation member may have one face
formed into a curved shape, and a main body having at least the first
electrode, the second electrode, the vibrating member, the first elastic
member, and the second elastic member may be provided on a face on an
opposite side of the one face.

[0021] In the invention, the first separation member may have a base and a
plurality of protrusions provided on one face of the base.

[0022] In the invention, the first separation member may be a member in
which a plurality of spaces having a predetermined shape are joined
together.

[0023] In the invention, the predetermined shape is a hexagonal shape.

[0024] In order to solve the above problems, according to the invention,
there is provided a speaker system comprising: a loudspeaker's main body
including: a first electrode having acoustic transmission property; a
second electrode having acoustic transmission property, and disposed so
as to be opposed to the first electrode; a vibrating member having
conductibility, and disposed between the first electrode and the second
electrode; a first elastic member having elasticity, insulation property,
and acoustic transmission property, and disposed between the vibrating
member and the first electrode; and a second elastic member having
elasticity, insulation property, and acoustic transmission property, and
disposed between the vibrating member and the second electrode; and a
separation member having insulation property and acoustic transmission
property, and disposed on an opposite side of a face of the first
electrode of the loudspeaker's main body, which is opposed to the first
elastic member.

[0025] In order to solve the above problems, according to the invention,
there is provided a separation member mounted on a loudspeaker's main
body having a first electrode having acoustic transmission property, a
second electrode having acoustic transmission property, and disposed so
as to be opposed to the first electrode, a vibrating member having
conductibility, and disposed between the first electrode and the second
electrode, a first elastic member having elasticity, insulation property,
and acoustic transmission property, and disposed between the vibrating
member and the first electrode, and a second elastic member having
elasticity, insulation property, and acoustic transmission property, and
disposed between the vibrating member and the second electrode, wherein
the separation member has insulation property and acoustic transmission
property and is disposed on an opposite side of a face of the first
electrode of the loudspeaker's main body, which is opposed to the first
elastic member.

Advantage of the Invention

[0026] The electrostatic loudspeaker according to the present invention
can radiate the acoustic wave generated from both faces of the vibrating
member thereof to the outside of the electrostatic loudspeaker even if
the electrostatic loudspeaker is installed so as to be made contact with
a shield through which the acoustic wave hardly passes.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is an external view showing an electrostatic loudspeaker
according to an embodiment of the present invention;

[0028]FIG. 2 is a schematic view showing the cross-section and electrical
configuration of the electrostatic loudspeaker;

[0030] FIGS. 4(a) and 4(b) are views illustrating the transmission of an
acoustic wave;

[0031] FIGS. 5(a) and 5(b) are views showing an electrostatic loudspeaker
in which the positional displacement thereof is suppressed according to a
modification of the present invention;

[0032]FIG. 6 is a view showing an electrostatic loudspeaker equipped with
an amplifier according to a modification of the present invention;

[0033]FIG. 7 is a sectional view showing an electrostatic loudspeaker
according to a modification of the present invention;

[0034] FIGS. 8(a) and 8(b) are external perspective views showing a
separation member according to a modification of the present invention;

[0035] FIGS. 9(a) and 9(b) are external perspective views showing a
separation member according to a modification of the present invention;

[0036]FIG. 10 is a schematic view showing a separation member and a
shield according to a modification of the present invention;

[0037] FIGS. 11(a), 11(b), and 11(c) are views showing the structure of a
separation member according to a modification of the present invention;

[0038] FIGS. 12(a), 12(b), and 12(c) are views showing the structure of a
separation member according to a modification of the present invention;

[0039] FIG. 13 is an exploded perspective view showing an electrostatic
loudspeaker according to a modification of the present invention;

[0040]FIG. 14 is a view showing the lower face of a separation member
according to a modification of the present invention;

[0041]FIG. 15 is a view showing an electrostatic loudspeaker secured to a
shield according to a modification of the present invention;

[0042] FIGS. 16(a) and 16(b) are views showing a separation member and a
holding member according to a modification of the present invention;

[0043] FIGS. 17(a) and 17(b) are views showing an electrostatic
loudspeaker secured to a shield according to a modification of the
present invention; and

[0044]FIG. 18 is a view showing the structures of hook members and a
separation member according to a modification of the present invention.

MODE FOR CARRYING OUT THE INVENTION

Embodiment

[0045]FIG. 1 is an external view showing an electrostatic loudspeaker 1
according to an embodiment of the present invention, and FIG. 2 is a
schematic view showing the cross-section and electrical configuration of
the electrostatic loudspeaker 1. In addition, FIG. 3 is an exploded
perspective view showing the electrostatic loudspeaker 1. In this
embodiment, the electrostatic loudspeaker 1 has a rectangular
parallelepiped shape. In the following descriptions of the figures, the
X, Y, and Z axes perpendicular to one another indicate directions, and it
is assumed that the left-right direction as viewed from the front of the
electrostatic loudspeaker 1 is the X-axis direction, that the depth
direction is the Y-axis direction, and that the height direction is the
Z-axis direction. Besides, it is assumed that "." written in "o" in each
figure means an arrow directed from the back to the front of the figure.
Moreover, "x" written in "o" in each figure means an arrow directed from
the front to the back of the figure. The term "front" herein denotes the
direction of a face for the convenience of description, but does not
denote that the electrostatic loudspeaker 1 is oriented in the front
direction when it is placed. When the electrostatic loudspeaker 1 is
placed, it may be placed in any direction as necessary. Still further,
the dimensions of the respective components shown in the figure are made
different from the actual dimensions thereof so that the shapes of the
components can be understood easily.

[0046] (Configurations of the Respective Components of the Electrostatic
Loudspeaker 1)

[0047] The electrostatic loudspeaker 1 is roughly divided into a main body
11 and a separation member 12.

[0048] First, the configurations of various sections constituting the main
body 11 of the electrostatic loudspeaker 1 will be described.

[0049] The main body 11 of the electrostatic loudspeaker 1 is the
so-called push-pull electrostatic loudspeaker and has a vibrating member
10, electrodes 20U and 20L, spacers 30U and 30L, and elastic members 40U
and 40L. In this embodiment, the configurations of the electrodes 20U and
20L are the same, and the configurations of the spacers 30U and 30L are
the same. Furthermore, the configurations of the elastic members 40U and
40L are also the same. Hence, in the case that it is not particularly
necessary to distinguish between the two in the respective members, the
descriptions of "U" and "L" are omitted.

[0050] The vibrating member 10 has a configuration in which a metal having
conductibility is evaporated or a conductive coating material is applied
to both faces of a film made of PET (polyethylene terephthalate), PP
(polypropylene), or the like to form conductive membranes. The vibrating
member 10 has a rectangular shape as viewed from the Z-axis direction,
and the dimension in the Z-axis direction is approximately several pm to
several ten pm. Furthermore, the vibrating member 10 has flexibility and
is deflected when a force is applied thereto.

[0051] The spacer 30 has insulation property and has a rectangular frame
shape as viewed from the Z-axis direction. Furthermore, the spacer 30 has
flexibility and is deflected when a force is applied thereto. The
dimension of the spacer 30 in the X-axis direction is the same as the
dimension of the electrode 20 in the X-axis direction, and the dimension
of the spacer 30 in the Y-axis direction is the same as the dimension of
the electrode 20 in the Y-axis direction. The dimension of the spacer 30U
in the Z-axis direction is the same as the dimension of the spacer 30L in
the Z-axis direction. The elastic member 40 is a member obtained by
heating and compressing cotton and allows air and sound to pass
therethrough. In other words, the elastic member 40 has acoustic
transmission property. Furthermore, the elastic member 40 has insulation
property and elasticity, and it is deformed when an external force is
applied thereto and returns to its original shape when the external force
is removed. In addition, the elastic member 40 has a rectangular shape as
viewed from the Z-axis direction.

[0052] The electrode 20 has a configuration in which a metal having
conductibility is evaporated or a conductive coating material is applied
to one face of a film having insulation property and made of PET, PP, or
the like. The electrode 20 has a plurality of through-holes 21 passing
through from the front face to the back face. The electrode 20 allows air
and sound to pass therethrough. In other words, the electrode 20 has
acoustic transmission property. In addition, the electrode 20 has
flexibility and is deflected when a force is applied thereto. The
electrode 20 has a rectangular shape as viewed from the Z-axis direction.
The dimensions of the electrode 20 in the X-axis direction and in the
Y-axis direction are longer than the dimensions of the vibrating member
10 in the X-axis direction and in the Y-axis direction.

[0053] Next, the configuration of the separation member 12 of the
electrostatic loudspeaker 1 will be described. The separation member 12
is a member that is used to separate the main body 11 from a shield to
provide an air layer. The term "shield" is an object, such as a floor
face, a wall face, or a pillar, which can make contact with the
electrostatic loudspeaker 1; an acoustic wave incident to the shield
hardly passes therethrough and is easily reflected thereby. The shape of
the surface of the shield is not limited to a flat face, but may be a
curved face or a face having unevenness. The term "separation" means a
state in which a certain object is placed away from a certain position.

[0054] The separation member 12 is a member obtained by heating and
compressing cotton and allows air and sound to pass therethrough. The
separation member 12 has insulation property and elasticity, and it is
deformed when an external force is applied thereto and returns to its
original shape when the external force is removed. The separation member
12 has a rectangular parallelepiped shape. In the separation member 12,
the face in the positive direction of the Z-axis is referred to as the
upper face thereof, the face in the negative direction of the Z-axis is
referred to as the lower face thereof, and the faces other than the upper
face and the lower face are referred to as the circumferential faces
thereof. The electrode 20L of the main body 11 is firmly bonded to the
upper face of the separation member 12 using an adhesive. The dimension
of the separation member 12 in the X-axis direction is the same as the
dimension of the main body 11 in the X-axis direction, and the dimension
of the separation member 12 in the Y-axis direction is the same as the
dimension of the main body 11 in the Y-axis direction. The dimension of
the separation member 12 in the Z-axis direction is approximately 5 to 6
cm, that is, a dimension adequate to allow an acoustic wave having passed
through the through-holes 21 to be radiated from the circumferential
faces of the separation member 12 to the outside of the electrostatic
loudspeaker 1. The dimension of the separation member 12 in the Z-axis
direction is not limited to 5 to 6 cm, but may be determined
appropriately depending on the intensity of the acoustic wave radiated
from the main body 11. It is supposed that the separation member 12 has
acoustic transmission property higher than that of the spacer 30.

[0055] (Structure of the Electrostatic Loudspeaker 1)

[0056] Next, the structure of the electrostatic loudspeaker 1 will be
described.

[0057] In the electrostatic loudspeaker 1, the spacer 30U and the spacer
30L are firmly bonded to each other with one side of the vibrating member
10 held between the lower face of the spacer 30U and the upper face of
the spacer 30L. Furthermore, in the electrostatic loudspeaker 1, the
electrode 20L is firmly bonded to the lower face of the spacer 30L with
the conductive face thereof oriented toward the vibrating member 10, and
the electrode 20U is firmly bonded to the upper face of the spacer 30U
with the conductive face thereof oriented toward the vibrating member 10.
Inside the frame-shaped spacer 30L, the elastic member 40L is disposed.
The elastic member 40L makes contact with the vibrating member 10 and the
electrode 20L. Furthermore, inside the frame-shaped spacer 30U, the
elastic member 40U is disposed. The elastic member 40U makes contact with
the vibrating member 10 and the electrode 20U. The separation member 12
is firmly bonded to the lower face of the electrode 20L using an
adhesive.

[0058] In this embodiment, only one side of the vibrating member 10 is
held between the spacer 30U and the spacer 30L, and the other three sides
are in a state of not being held between the spacer 30U and the spacer
30L. In other words, the vibrating member 10 is placed between the
electrode 20U and the electrode 20L in a state that no tension is applied
thereto. However, since the elastic member 40U and the elastic member 40L
support the vibrating member 10 while holding it therebetween, when the
vibrating member 10 is not in a state of being driven, the vibrating
member 10 is placed at an intermediate position between the electrode 20U
and the electrode 20L. Moreover, since no tension is applied to the
vibrating member 10, even if the electrostatic loudspeaker 1 is
deflected, no tension is applied to the vibrating member 10, and no
elongation occurs in the vibrating member 10.

[0059] (Electrical Configuration of the Electrostatic Loudspeaker 1)

[0060] Next, the electrical configuration of the electrostatic loudspeaker
1 will be described. As shown in FIG. 2, a driver 100 is connected to the
electrostatic loudspeaker 1. The driver 100 is equipped with a
transformer 50, an input section 60, and a bias supply 70. An acoustic
signal is input to the input section 60 from the outside. The bias supply
70 is connected to the conductive portion of the vibrating member 10 and
to the middle point on the output side of the transformer 50. The bias
supply 70 supplies a DC bias to the vibrating member 10. The conductive
portion of the electrode 20U is connected to one terminal on the output
side of the transformer 50, and the conductive portion of the electrode
20L is connected to the other terminal on the output side of the
transformer 50. The input side of the transformer 50 is connected to the
input section 60. In this configuration, when an acoustic signal is input
to the input section 60, a voltage corresponding to the input acoustic
signal is applied across the electrodes 20, whereby the electrostatic
loudspeaker 1 operates as a push-pull electrostatic loudspeaker.

[0061] (Operation of the Electrostatic Loudspeaker 1)

[0062] Next, the operation of the electrostatic loudspeaker 1 will be
described. When an acoustic signal is input to the input section 60, a
voltage corresponding to the input acoustic signal is applied across the
electrode 20U and the electrode 20L from the transformer 50. When a
potential difference occurs between the electrode 20U and the electrode
20L due to the applied voltage, an electrostatic force is exerted to the
vibrating member 10 placed between the electrode 20U and the electrode
20L in a direction in which the vibrating member 10 is attracted to
either the electrode 20U or the electrode 20L.

[0063] For example, it is assumed that an acoustic signal is input to the
input section 60, this acoustic signal is supplied to the transformer 50,
a plus voltage is applied to the electrode 20U, and a minus voltage is
applied to the electrode 20L. Since a plus voltage is applied from the
bias supply 70 to the vibrating member 10, the vibrating member 10 repels
the electrode 20U to which the plus voltage is applied, but is attracted
to the electrode 20L to which the minus voltage is applied, thereby being
displaced toward the electrode 20L. Furthermore, it is assumed that an
acoustic signal is input to the input section 60, this acoustic signal is
supplied to the transformer 50, a minus voltage is applied to the
electrode 20U, and a plus voltage is applied to the electrode 20L. The
vibrating member 10 repels the electrode 20L to which the plus voltage is
applied, but is attracted to the electrode 20U to which the minus voltage
is applied, thereby being displaced toward the electrode 20U.

[0064] In this way, the vibrating member 10 is displaced toward the
electrode 20U or toward the electrode 20L depending on the acoustic
signal and the direction of the displacement changes sequentially,
whereby vibration is generated and an acoustic wave corresponding to the
vibration state (frequency, amplitude, and phase) is generated from the
vibrating member 10. The generated acoustic wave passes through the
elastic members 40 and the electrodes 20, and is radiated to the outside
of the main body 11 of the electrostatic loudspeaker 1.

[0065] The transmission paths of the acoustic wave generated from the
vibrating member 10 will be described.

[0066] FIGS. 4(a) and 4(b) are views illustrating the transmission of the
acoustic wave. FIG. 4(a) shows an electrostatic loudspeaker 900 according
to a related art, not equipped with the separation member 12, and FIG.
4(b) shows the electrostatic loudspeaker 1 according to this embodiment,
equipped with the separation member 12. Respective components
constituting the electrostatic loudspeaker 900 are the same as those
constituting the main body 11 of the electrostatic loudspeaker 1. Hence,
the descriptions of the respective components constituting the
electrostatic loudspeaker 900 are omitted.

[0067] First, the transmission paths of the acoustic wave radiated from
the electrostatic loudspeaker 900 will be described. The electrostatic
loudspeaker 900 is installed such that the electrode 20L is made contact
with a shield S1. It is assumed that the shield S1 is a floor face, for
example, on which objects can be placed. The acoustic wave generated from
the vibrating member 10 is radiated in the positive direction of the
Z-axis and in the negative direction of the Z-axis. The acoustic wave
generated in the positive direction of the Z-axis passes through the
elastic member 40U and the electrode 20U and is radiated to the outside
of the electrostatic loudspeaker 900. On the other hand, the acoustic
wave generated in the negative direction of the Z-axis passes through the
elastic member 40L and enters the through-holes 21L of the electrode 20L.
However, since the electrode 20L makes contact with the shield S1, the
through-holes 21L are blocked by the shield S1. As a result, the acoustic
wave having entered the through-holes 21L is reflected by the shield S1
and cannot pass through the through-holes 21L. In other words, the
acoustic wave generated in the negative direction of the Z-axis is not
radiated to the outside of the electrostatic loudspeaker 900.

[0068] Next, the transmission paths of the acoustic wave radiated from the
electrostatic loudspeaker 1 according to the present invention equipped
with the separation member 12 shown in FIG. 4(b) will be described. The
electrostatic loudspeaker 1 is installed such that the lower face of the
separation member 12 is made contact with the shield S1. The acoustic
wave generated from the vibrating member 10 is radiated in the positive
direction of the Z-axis and in the negative direction of the Z-axis. The
acoustic wave generated in the positive direction of the Z-axis passes
through the elastic member 40U and the electrode 20U and is radiated to
the outside of the electrostatic loudspeaker 1. On the other hand, the
acoustic wave generated in the negative direction of the Z-axis passes
through the elastic member 40L and enters the through-holes 21L of the
electrode 20L. In this case, since the electrode 20L makes contact with
the separation member 12, the through-holes 21L are blocked by the
separation member 12. However, since the separation member 12 allows air
and sound to pass therethrough, the acoustic wave having entered the
through-holes 21L can pass through the through-holes 21L. As a result,
the acoustic wave having passed through the through-holes 21L passes
through the separation member 12 and is reflected by the shield S1, and
then radiated from the circumferential faces of the separation member 12
to the outside of the electrostatic loudspeaker 1.

[0069] As described above, in the electrostatic loudspeaker 1, the
through-holes 21L are not blocked by the shield. Hence, in the
electrostatic loudspeaker 1, the acoustic wave having passed through the
through-holes 21L can be radiated from the circumferential faces of the
separation member 12. In other words, the electrostatic loudspeaker 1 can
radiate the acoustic wave generated from both faces of the vibrating
member to the outside of the electrostatic loudspeaker.

[0070] For example, in the case that the separation member 12 is not
provided between the vibrating member 10 and the shield and that no
distance is securely obtained between the vibrating member 10 and the
shield, the air being present between the vibrating member 10 and the
shield is difficult to move even if the vibrating member 10 vibrates, and
the viscosity of the air being present between the vibrating member 10
and the shield affects the vibration of the vibrating member 10, whereby
the sound pressure is lowered. On the other hand, in the electrostatic
loudspeaker 1 according to this embodiment, a distance is securely
obtained between the vibrating member 10 and the shield by virtue of the
separation member 12, and the air being present between the vibrating
member 10 and the shield is easy to move. Hence, when this case is
compared with the case in which the separation member 12 does not exist
between the vibrating member 10 and the shield and no distance is
securely obtained therebetween, the vibrating member 10 is less affected
by the viscosity of the air being present between the shield and the
vibrating member 10, whereby the sound pressure of the sound to be output
can be raised.

[0071] In addition, the electrostatic loudspeaker 1 is formed of
components that are deflected when a force is applied thereto. Hence, the
electrostatic loudspeaker 1 can be deflected, thereby being able to be
installed not only on a flat face but also on a curved face.

Modifications

[0072] The above-mentioned embodiment is just one example of the
embodiment according to the present invention. The present invention can
be implemented in embodiments in which the following modifications are
applied to the above-mentioned embodiment. The following modifications
may be appropriately combined and implemented as necessary.

[0073] (Modification 1)

[0074] In the above-mentioned embodiment, the vibrating member 10 is a
member obtained by evaporating a conductive metal or by applying a
conductive coating material onto both faces of a film, but may be a
member obtained by evaporating a conductive metal or by applying a
conductive coating material onto one face of the film. In addition, the
vibrating member 10 is not limited to be made of PET or PP, but may be a
member obtained by evaporating a conductive metal or by applying a
conductive coating material onto a film of another synthetic resin.

[0075] In the above-mentioned embodiment, the electrode 20 is provided
with the plurality of through-holes 21 passing therethrough from the
front face to the back face. However, the electrostatic loudspeaker 1 is
not limited to have the through-holes 21, but should only have a
configuration in which at least an acoustic wave can be radiated to the
outside of the electrostatic loudspeaker 1. For example, the electrode 20
may be a cloth-like electrode woven with conductive fiber or may be made
of conductive non-woven cloth; the electrode should only have
conductibility and flexibility and allow air and sound to pass
therethrough. Furthermore, the electrode 20 is a member obtained by
evaporating a conductive metal or by applying a conductive coating
material onto one face of a film, but may be a member obtained by
evaporating a conductive metal or by applying a conductive coating
material onto both faces of the film. In addition, the electrode 20 is
not limited to be made of PET or PP, but may be a member obtained by
evaporating a conductive metal or by applying a conductive coating
material onto a sheet of another synthetic resin.

[0076] (Modification 2)

[0077] In the above-mentioned embodiment, the main body 11 and the
separation member 12 of the electrostatic loudspeaker 1 are firmly bonded
to each other using an adhesive. However, without the main body 11 and
the separation member 12 firmly bonded to each other, they may be
configured so that their positions are not displaced relative to each
other.

[0078] FIGS. 5(a) and 5(b) are views showing an electrostatic loudspeaker
1a in which the positional displacement thereof is suppressed according
to a modification of the present invention. In FIG. 5(a), a restraining
member 131 and a restraining member 132 are an endless belt, have
insulation property, and allow air and sound to pass therethrough. The
restraining member 131 is wound in the Y-axis direction so that the main
body 11 and the separation member 12 are integrated into one body,
whereby the position of the main body 11 and the position of the
separation member 12 are suppressed from being displaced relative to each
other in the Y-axis direction and in the Z-axis direction. Furthermore,
the restraining member 132 is wound in the X-axis direction so that the
main body 11 and the separation member 12 are integrated into one body,
whereby the position of the main body 11 and the position of the
separation member 12 are suppressed from being displaced relative to each
other in the X-axis direction and in the Z-axis direction. As a result,
the main body 11 and the separation member 12 are suppressed from being
displaced relative to each other as in the case that they are firmly
bonded to each other using an adhesive.

[0079] Furthermore, although the relative positional displacement is
suppressed by winding the restraining members on the surfaces of the main
body 11 and the separation member 12 as shown in FIG. 5(a), the relative
positional displacement may be suppressed by covering the entire areas of
the surfaces of the main body 11 and the separation member 12 using a
restraining member as shown in FIG. 5(b). In FIG. 5(b), a restraining
member 133 is a piece of cloth formed to cover the surfaces of the main
body 11 and the separation member 12 by integrating them into one body,
and the cloth has insulation property and allows air and sound to pass
therethrough. The restraining member 133 covers the main body 11 and the
separation member 12 by integrating them into one body, whereby the
positions of the main body 11 and the separation member 12 are suppressed
from being displaced relative to each other in the X-axis direction, in
the Y-axis direction, and in the Z-axis direction. As a result, the main
body 11 and the separation member 12 are suppressed from being displaced
relative to each other as in the case that they are firmly bonded to each
other using an adhesive.

[0080] (Modification 3)

[0081] The electrostatic loudspeaker may be configured so as to be
integrated with an amplifier for amplifying an acoustic signal.

[0082]FIG. 6 is a view showing an electrostatic loudspeaker 1b equipped
with an amplifier according to a modification of the present invention.
In the electrostatic loudspeaker 1b, an amplifier 14 is mounted on a
circumferential face thereof. The amplifier 14 amplifies an acoustic
signal input from the outside and outputs the acoustic signal. The
acoustic signal output from the amplifier 14 is input to the input
section 60 of the driver 100 provided for the main body 11. In the
electrostatic loudspeaker 1b configured as described above, no amplifier
is required to be connected thereto separately, and it is not required to
consider the disposition of the amplifier. In other words, the
installation of the electrostatic loudspeaker 1b is made easy.
Furthermore, in the electrostatic loudspeaker 1b, the main body 11 is not
required to be equipped with the driver 100. In this case, a function
equivalent to that of the driver 100 may be provided as the function of
the amplifier 14, for example.

[0083] (Modification 4)

[0084] In the above-mentioned embodiment, the separation member 12 is
provided between the shield and the electrode 20L opposed to the shield.
However, the position in which the separation member 12 is provided is
not limited to this position.

[0085]FIG. 7 is a sectional view showing an electrostatic loudspeaker 1c
according to a modification of the present invention. As shown in the
figure, in the electrostatic loudspeaker 1c, a separation member 12L is
firmly bonded to the lower face of the electrode 20L, and a separation
member 12U is firmly bonded to the upper face of the electrode 20U. In
other words, in the electrostatic loudspeaker 1c, the main body 11 is
held between the separation member 12U and the separation member 12L. In
the electrostatic loudspeaker 1c configured as described above, even if
the separation member 12U is made contact with a shield, the
through-holes 21U are not blocked by the shield. Furthermore, even if the
separation member 12L is made contact with a shield, the through-holes
21L are not blocked by the shield. In other words, in the electrostatic
loudspeaker 1c, even if either the separation member 12U or the
separation member 12L is made contact with a shield, the acoustic wave
generated from both faces of the vibrating member can be radiated to the
outside of the electrostatic loudspeaker 1c.

[0086] Moreover, since the electrostatic loudspeaker 1c is configured so
that the main body 11 is held between the separation members 12 having
elasticity, it may be possible that an impact applied to the
electrostatic loudspeaker 1c is absorbed by the separation members 12 and
the impact transmitted to the main body 11 is reduced. Still further,
since the electrostatic loudspeaker 1c is configured so that the
electrode 20 is covered with the separation members 12, it may be
possible that the occurrence of electric shock and short-circuit is
suppressed.

[0087] (Modification 5)

[0088] The shape of the separation member is not limited to a cube, but
may be a pillar or a cone. In addition, the face of the separation member
on which the main body is provided is not limited to be a flat face, but
may be a curved face.

[0089]FIG. 8(a) is an external perspective view showing a separation
member 12d, and FIG. 8(b) is a schematic view showing the transmission
paths of an acoustic wave. As shown in the figures, the upper face of the
separation member 12d is formed into a convex shape. In the case that an
electrostatic loudspeaker is configured by bonding the main body to the
area 127d on the upper face of the separation member 12d, the shape of
upper face of the main body becomes a convex shape similar to the shape
of the separation member 12d. In this case, since the acoustic wave
radiated from the main body is diffused along the transmission paths Ld
shown in FIG. 8(b), the wave is diffused to a space wider than the space
of the area 127d in the Z-axis direction.

[0090]FIG. 9(a) is an external perspective view showing a separation
member 12e, and FIG. 9(b) is a schematic view showing the transmission
paths of an acoustic wave. As shown in the figures, the upper face of the
separation member 12e is formed into a concave shape. In the case that an
electrostatic loudspeaker is configured by bonding the main body to the
area 127e on the upper face of the separation member 12e, the shape of
the upper face of the main body becomes a concave shape similar to the
shape of the separation member 12e. In this case, since the acoustic wave
radiated from the main body is diffused along the transmission paths Le
shown in FIG. 9(b), the wave is diffused to a space narrower than the
space of the area 127e in the Z-axis direction.

[0091] Hence, for example, in the case that an acoustic wave is desired to
be radiated to a wide space, the main body should only be provided on the
separation member formed into a convex shape. Furthermore, in the case
that an acoustic wave is desired to be radiated to a narrow space, the
main body should only be provided on the separation member formed into a
concave shape. The shape of the separation member and the position in
which the main body is provided on the separation member are arbitrary
and should only be determined depending on the direction in which the
acoustic wave is desired to be radiated.

[0092] The shape of the separation member may be determined to a shape
matched to the shape of a shield.

[0093]FIG. 10 is a schematic view showing a separation member 2f and a
shield S3 according to a modification of the present invention. In FIG.
10, the shield S3 is a cylinder having a radius of R1. In this case, the
separation member 12f should only be determined so as to have a shape to
be wound around the outer circumferential face of the shield S3, that is,
so that a curved face of a radius of R1 becomes the inner circumferential
face thereof. The separation member 12f configured as described above can
be provided for the shield S3 without being deflected. Furthermore, it is
assumed that the separation member 12f is determined so that a curved
face of a radius R2 (R1<R2) becomes the outer circumferential face
thereof. In this case, an electrostatic loudspeaker is configured by
bonding the main body to the outer circumferential face of the separation
member 12f. The outer circumferential face of the separation member 12f
is not limited to a curved face, but may be formed into a flat face.

[0094] The separation member may be configured so as to be deformed more
easily than that having a cubic shape. FIGS. 11(a), 11(b), and 11(c) are
views showing the structure of a separation member 12g according to a
modification of the present invention. FIG. 11(a) is a bottom view
showing the separation member 12g, FIG. 11(b) is a front view showing the
separation member 12g, and FIG. 11(c) is a side view showing the
separation member 12g. An electrostatic loudspeaker is configured by
bonding the main body to the upper face of the separation member 12g. The
separation member 12g has a rectangular shape as viewed from the Z-axis
direction and is equipped with a base 124g and a plurality of protrusions
125g. The base 124g and the protrusions 125g are obtained by heating and
compressing cotton and allow air and sound to pass therethrough. The
separation member 12g has insulation property and elasticity, and it is
deformed when an external force is applied thereto and returns to its
original shape when the external force is removed. On the lower face of
the base 124g, the plurality of protrusions 125g are provided at
predetermined intervals (spacing 126g) in the X-axis direction and in the
Y-axis direction. The protrusions 125g have a quadrangular prism shape,
and each protrusion 125g has a rectangular parallelepiped shape in which
the side in the X-axis direction is equal to the side in the Y-axis
direction. Furthermore, one end of the protrusion 125g is a fixed end
secured to the base 124g, and the other end of the protrusion 125g is a
free end not secured to the base 124g. For example, it is assumed that
the base 124g is bent convexly at the center of the lower face. In this
case, the spacing 126g between the protrusions 125g adjacent to each
other becomes wider in the direction from the fixed end to the free end.
In addition, it is assumed that the base 124g is bent concavely at the
center of the lower face. In this case, the spacing 126g between the
protrusions 125g adjacent to each other becomes narrower in the direction
from the fixed end to the free end. In other words, the separation member
12g is configured so that the free end of the protrusion 125g is movable
as the base 124g is bent, whereby the separation member 12g can be bent
without causing expansion or contraction of the lower face of the
separation member 12g. Hence, the separation member 12g having the
plurality of protrusions 125g can be bent more flexibly depending on the
shape of a shield than a separation member having no protrusions.
Furthermore, since the separation member 12g can be wound, it is stored
and carried easily. Although the plurality of protrusions 125g are
provided at predetermined intervals in the X-axis direction and in the
Y-axis direction on the lower face of the base 124g, the protrusions 125g
may be provided at predetermined intervals either in the X-axis direction
or in the Y-axis direction.

[0095] FIGS. 12(a), 12(b), and 12(c) are views showing the structure of a
separation member 12h according to a modification of the present
invention. FIG. 12(a) is a bottom view showing the separation member 12h,
FIG. 12(b) is a front view showing the separation member 12h, and FIG.
12(c) is a side view showing the separation member 12h. An electrostatic
loudspeaker is configured by bonding the main body to the upper face of
the separation member 12h, and the separation member is provided by
making the lower face thereof into contact with a shield. The separation
member 12h has a rectangular shape as viewed from the Z-axis direction
and is equipped with a base 124h and a plurality of protrusions 125h. It
is assumed that the base 124h and the protrusions 125h are formed of the
same material as that of the base 124g and the protrusions 125g. On the
lower face of the base 124h, the plurality of protrusions 125h are
provided at predetermined intervals (spacing 126h) in the Y-axis
direction. The protrusions 125h have a quadrangular prism shape, and each
protrusion 125h has a rectangular parallelepiped shape extended in the
X-axis direction in which the side in the X-axis direction is longer than
the side in the Y-axis direction. Furthermore, one end of the protrusion
125h is a fixed end secured to the base 124h, and the other end of the
protrusion 125h is a free end not secured to the base 124h. For example,
it is assumed that the base 124h is bent convexly at the center of the
lower face. In this case, the spacing 126h between the protrusions 125h
adjacent to each other becomes wider in the direction from the fixed end
to the free end. In addition, it is assumed that the base 124h is bent
concavely at the center of the lower face. In this case, the spacing 126h
between the protrusions 125h adjacent to each other becomes narrower in
the direction from the fixed end to the free end. In other words, the
separation member 12h is configured so that the free end of the
protrusion 125h is movable as the base 124h is bent, whereby the
separation member 12h can be bent without causing expansion or
contraction of the lower face of the separation member 12h. Hence, the
separation member 12h having the plurality of protrusions 125h can be
bent more flexibly depending on the shape of a shield than a separation
member having no protrusions. Furthermore, since the separation member
12h can be wound, it is stored and carried easily.

[0096] (Modification 6)

[0097] FIG. 13 is an exploded perspective view showing an electrostatic
loudspeaker 1i according to a modification of the present invention.

[0098] A separation member 12i is a non-conductive member made of thin
paper or the like allowing air and sound to pass therethrough and has a
shape in which a plurality of spaces (cells) having a hexagonal shape as
viewed from the above are joined together without clearances as in the
case of a honeycomb. Innumerable holes may be formed in the thin paper to
allow air and sound to easily pass through between the cells. When the
electrostatic loudspeaker 1i is configured, one end face of the
separation member 12i in the height direction thereof (in a direction
orthogonal to the cross section of the hexagon) is made close contact
with the surface of the electrode 20L of the main body 11 and the
separation member 12i is firmly bonded to the electrode 20L using an
adhesive or an adhesive tape. In this way, the electrostatic loudspeaker
1i having the separation member 12i is configured. In the electrostatic
loudspeaker 1i, the electrode 20L of the main body 11 is bonded to the
separation member 12i that allows air and sound to passing therethrough;
hence, the acoustic wave generated from both faces of the vibrating
member can be radiated to the outside of the electrostatic loudspeaker
1i. Although the shape of the cells of the separation member 12i is a
hexagonal shape, the shape may be other shapes, such as a rectangular
shape, a wavy shape or a trapezoidal shape.

[0099] (Modification 7)

[0100] The separation member may have a shape capable of being secured to
a wall face or the like.

[0101]FIG. 14 is a view showing the lower face of a separation member 12j
according to a modification of the present invention. FIG. 15 is a
sectional view taken on line A-A of an electrostatic loudspeaker 1j
equipped with the separation member 12j shown in FIG. 14 and is a view
showing the electrostatic loudspeaker 1j secured to a shield S2. It is
assumed that the shield S2 is, for example, a wall on which no object can
be placed. Furthermore, a holding member S21j is, for example, a screw or
a nail, and part thereof is inserted into the shield S2, thereby being
secured to the shield S2. The description is herein returned to FIG. 14.
In the separation member 12j, a hole 128j opening from the inside to the
lower face of the separation member 12j is provided. The hole 128j has a
circular shape as viewed from the Z-axis direction and is open so as to
have a size adequate to allow the holding member S21j to be inserted
therein. As shown in FIG. 15, the electrostatic loudspeaker 1j is
configured by bonding the main body 11 to the upper face of the
separation member 12j. Then, the holding member S21j is inserted into the
hole 128j, whereby the electrostatic loudspeaker 1j is secured to the
shield S2. In other words, since the electrostatic loudspeaker 1j is not
required to be separately equipped with members for securing the
electrostatic loudspeaker to the shield S2, the electrostatic loudspeaker
can be installed easily on a shield, such as a wall face, on which no
object can be placed.

[0102] The hole provided in the separation member is not limited to a hole
having a circular shape.

[0103] FIGS. 16(a) and 16(b) are views showing a separation member 12k and
a holding member S21k according to a modification of the present
invention. FIG. 16(a) is a bottom view showing the separation member 12k
according to the modification of the present invention. FIG. 16(b) is a
view showing the structures of the shield S2 and the holding member S21k.
Furthermore, the holding member S21k is, for example, a screw or a nail,
and includes a body S211k and a head S212k. Part of the body S211k of the
holding member S21k is inserted into the shield S2, whereby the holding
member S21k is secured to the shield S2. The head S212k is formed so as
to be thicker than the body S211k.

[0104] The description is herein returned to FIG. 16(a). In the separation
member 12k, a hole 128k opening from the inside to the lower face of the
separation member 12k is provided. The hole 128k has a rectangular shape
as viewed from the Z-axis direction. In the hole 128k, out of the two
sides along the X-axis direction, the side in the positive direction of
the Y-axis is referred to as a side X1, and the side in the negative
direction of the Y-axis is referred to as a side X2; and out of the two
sides along the Y-axis direction, the side in the positive direction of
the X-axis is referred to as a side Y1, and the side in the negative
direction of the X-axis is referred to as a side Y2. Furthermore, the
dimension of the side Y1 and the side Y2 is A1, and the dimension of the
side X1 and the side X2 is A2. A convex 122k is provided on the wall face
of the opening of the hole 128k so as to protrude therefrom. The convex
122k is equipped with a first convex 1221k, a second convex 1222k, and a
third convex 1223k. The first convex 1221k is provided so as to protrude
by a dimension A3 from the wall face of the opening along the side X2.
The second convex 1222k is provided so as to protrude by the dimension A3
in the negative direction of the X-axis from the wall face of the opening
along the side Y1. The third convex 1223k is provided so as to protrude
by the dimension A3 in the positive direction of the X-axis from the wall
face of the opening along the side Y2. In other words, the convex 122k is
formed into a U-shape having two sides extending along the Y-axis
direction and connected and one side extending along the X-axis
direction, wherein each side is provided so as to protrude by the
dimension A3 from each wall face of the opening formed along each side.
It is configured that the dimension (A2) of the hole 128k in the X-axis
direction is longer than the total of the dimension (A3) of the
protruding portion of the second convex 1222k and the dimension (A3) of
the protruding portion of the third convex 1223k, and that the dimension
(A1) of the hole 128k in the Y-axis direction is longer than the
dimension (A3) of the protruding portion of the first convex 1221k. The
opening of the hole 128k formed as described above is roughly divided
into a first space 1231k having the dimension A2 in the X-axis direction
and a second space 1232k having a dimension shorter than the dimension
(A2) of the first space 1231k by the total of the dimension (A3) of the
protruding portion of the second convex 1222k and the dimension (A3) of
the protruding portion of the third convex 1223k. The first space 1231k
is a space through which the head S212k of the holding member S21k can
pass, and the second space 1232k is a space through which the head S212k
of the holding member S21k cannot pass but only the body S211k can pass.
Furthermore, the first space 1231k and the second space 1232k are
continuous to each other, and the holding member S21k can move in the
respective spaces. As shown in FIGS. 17(a) and 17(b), an electrostatic
loudspeaker 1k is configured by bonding the main body 11 to the upper
face of the separation member 12k. Next, an example in which the
electrostatic loudspeaker 1k is secured to the holding member S21k
provided in the shield S2 is shown.

[0105] FIGS. 17(a) and 17(b) are views taken on line B-B of the
electrostatic loudspeaker 1k equipped with the separation member 12k
shown in FIG. 16(a) and views showing the electrostatic loudspeaker 1k
secured to the shield S2. First, as shown in FIG. 17(a), the holding
member S21k is inserted into the hole 128k of the electrostatic
loudspeaker 1k. At this time, the head S212k of the holding member S21k
is in a state of being positioned inside the hole 128k, and part of the
body S211k is in a state of being positioned in the first space 1231k.
Then, as shown in FIG. 17(b), in the state in which the holding member
S21k is inserted in the hole 128k, the electrostatic loudspeaker 1k is
moved in the positive direction of the Y-axis direction until the first
convex 1221k makes contact with the body S211k. At this time, the head
S212k is in a state of being positioned inside the hole 128k, and part of
the body S211k is in a state of being positioned in the second space
1232k. Since the second space 1232k is in a state of being enclosed with
the convex 122k formed into a U-shape, the head S212k cannot pass through
the space, and only the body S211k can pass through the space. Hence, the
movement of the electrostatic loudspeaker 1k is restricted by the holding
member S21k not only in the directions around the convex 122k but also in
the positive direction of the Z-axis direction. Since the gravitational
force is applied in the positive direction of the Y-axis direction, the
electrostatic loudspeaker 1k does not move in the negative direction of
the Y-axis direction. In other words, the electrostatic loudspeaker 1k is
restricted from moving in all the directions, thereby being secured to
the shield S2. Hence, since the electrostatic loudspeaker 1k equipped
with the separation member 12k shown in FIG. 16(a) is not required to be
separately equipped with members for securing the electrostatic
loudspeaker to the shield S2, the electrostatic loudspeaker can be
installed easily on a place, such as a wall face, on which no object can
be placed.

[0106] One or more holes may be provided in the lower face of the
separation member. In addition, the shape of the hole is not limited to a
rectangular shape, but the hole should only be provided with a convex
that is roughly divided into a space through which the head of the
holding member can pass and a space through which the head of the holding
member cannot pass and through which only the body can pass.

[0107] The shield S2 is not limited to a fixed face, such as a wall face,
but may be a movable face, such as a partition. In addition, the lower
face of the electrostatic loudspeaker may be bonded to the shield S2
using an adhesive or an adhesive tape, for example. The shape of the
electrostatic loudspeaker is not limited to a rectangular shape, but may
be other shapes, such as a polygonal shape, a circular shape, or an
elliptic shape.

[0108] In the above-mentioned embodiment, the electrostatic loudspeaker is
secured to the shield by inserting the holding member into the hole
provided in the lower face of the separation member; however, the method
for securing the electrostatic loudspeaker to the shield is not limited
to this method.

[0109]FIG. 18 is a view showing the structures of hook members and a
separation member according to a modification of the present invention.

[0110] It is assumed that a shield S4 is an object, such as a floor face,
a wall face, or a pillar, that can be made contact with the electrostatic
loudspeaker and is an object through which an entered acoustic wave
hardly passes and by which the entered acoustic wave is reflected easily.
Furthermore, the shield S4 is provided with hook members S41 in the
circumferential sections of a position where an electrostatic loudspeaker
1m is installed. In the electrostatic loudspeaker 1m, holes 128m into
which the hook members S41 are inserted are provided in the
circumferential faces of the separation member 12m. Then, the hook
members S41 are inserted into the holes 128m, whereby it may be possible
that the electrostatic loudspeaker 1m is secured to the shield S4.

[0111] (Modification 8)

[0112] The separation member is not limited to be made of cotton, but
should only be made of a material, such as urethane foam, non-woven
cloth, or glass wool, allowing air and sound to pass therethrough.
Furthermore, the separation member is not limited to be formed by the
method in which a material is compressed while being heated, but may be
formed by providing a plurality of holes in a member formed into a plate
shape, for example. The electrostatic loudspeaker may be formed of
electrodes, spacers, elastic members, and a separation member having no
flexibility and no elasticity.

[0113] (Modification 9)

[0114] In the above-mentioned embodiment, the vibrating member 10 is
supported because one side of the vibrating member 10 is held between the
lower face of the spacer 30U and the upper face of the spacer 30L.
However, the main body 11 of the electrostatic loudspeaker 1 is not
required to be equipped with the spacers 30. In this case, it may be
possible that, for example, the vibrating member 10 is disposed between
the lower face of the elastic member 40U and the upper face of the
elastic member 40L, an adhesive is applied in a width of several mm from
the edges in the X-axis direction and from the edges in the Y-axis
direction to the inside, and the vibrating member is firmly bonded to the
elastic member 40U and the elastic member 40L.